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中文
Table of Content
24 April 1999, Volume 20 Issue 4
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Articles
Synthesis and Characterization of Lamellar Structural Materials Ni
2
P
2
S
6
by Room Temperature Solid State Reaction
HUANG Zhong-Le, CHEN Jian-Gu, MAO Shao-Yu, ZHAO Jing-Tai, ZHAN Meng-Xiong, ZHENG Lan-Sun
1999, 20(4): 499-502.
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Results of XRD and Raman spectra show the successful preparation of lamellar structural materials Ni
2
P
2
S
6
by a new synthetic route room temperature solid state reaction. Compared with the traditional high temperature solid state reaction, the preparation method adopted here has the following advantages: fast reaction rate, low energy cost, high homogeneity of final products and the facility of preparation in quantity. Study of TG-DTA shows the final product Ni
2
P
2
O
7
and the existence of an intermediate metastable Ni
2
P
2
O
6
phase of Ni
2
P
2
S
6
thermo-oxidation in air.
Sol-Gel Synthesis and Magnetic Properties of CoFe
2-x
RE
x
O
4
(RE=Tb,Dy) Nanocrystalline Films
CHENG Fu-Xiang, KUANG Jun-Feng, LIAO Chun-Sheng, XU Zhi-Gang, YAN Chun-Hua
1999, 20(4): 503-506.
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The nanocrystalline thin films of CoFe
2-x
RE
x
O
4
(RE=Tb,Dy) were fabricated by sol-gel processing. By varying the doping content of rare earth ions, x, and the annealing conditions, the difficult crystallization of spinel phase was found for the samples with x>0.3, which is ascribed to te large radii of rare earth ions. AFM observation indicated that the grain size can be controlled between 20~50 nm and the sol-gel derived thin films have a surface with a low roughness of 4~5 nm. The doping of Tb
3+
and Dy
3+
ions inside spinel can enhance the coercive force of CoFe
2
O
4
films.
Synthesis of Lamellar Mesostructured Alumina by Supramolecular Templating
QI Li-Min, MA Ji-Ming
1999, 20(4): 507-510.
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Lamellar mesostructured alumina was synthesized at room temperature by using alkyl sulfates as templates. The effects of the length of the surfactant alkyl chain and the ratio of mixed surfactants on the structural data of the obtained lamellar mesophases were investigated. It was revealed that when single surfactants were used as templates, the interlayer spacing(
d
) as well as the long-range order of the lamellar structure increases with increasing alkyl chain length. When the carbon number(
n
) of the alkyl chains varies from 8 to 12, the plot of d versus n is linear with a slope of 0.205 nm/carbon atom, which indicates that for
n
=8~12, the thickness of the inorganic layers keeps nearly constant and the alkyl chains are arranged as double layers between the inorganic layers with a tilt angle of
ca
. 53. If mixed surfactants C
8
H
17
SO
4
Na-C
14
H
29
SO
4
Na are used as mixed templates, when the molar fraction(x) of C
14
H
29
SO
4
Na varies in the range of 0<x≤0.5, the int erlayer spacing remains essentially unchanged and approximates to the case of using a single surfactant with an average carbon number of 11 as template. On the other hand, when x>0.5, the interlayer spacing increases gradually with x. This result has been interpreted in terms of a proposed structure model for the molecular arrangement of mixed surfactants between the inorganic layers.
Hydrothermal Synthesis and Transport Property of Cubic KNb
0.77
Al
0.23
O
2.77
LI Guang-She, LI Li-Ping, WANG Min-Qiang, FENG Shou-Hua, YAO Xi
1999, 20(4): 511-514.
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Cubic KNb
0.77
Al
0.23
O
2.77
is initially synthesized by low temperature hydrothermal synthesis, whereas high temperature ceramic method can only produce the orthorhombic phase of the parent KNbO
3
structure. By tuning the niobium species and KOH concentration, we have obtained orthorhombic KNbO
3
and an intermediate phase. The cubic product was examined by X-ray diffraction, differential scanning calorimeter, and X-ray photoelectron spectroscopy. High temperature treatment up to 1000 did not result in phase transition, reflecting a high structural stability. The transport mechanism can be ascribed to the small polarons. However for the orthorhombic counterpart, the discontinuty may be arised from the structural transformation due to the structuraLINstability.
Preparation and Characterization of Quantum Paraelectric La
1/2
Na
1/2
TiO
3
Nanocrystals
ZHANG Wei-Feng, ZHANG Xing-Tang, GUO Hong, FANG Jiang-Lin, ZHANG Ming-Sheng
1999, 20(4): 515-518.
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Quantum paraelectric La
1/2
Na
1/2
TiO
3
nanocrystals have successfully been prepared by using improved sol-gel method in which absolute alcohol and stearic acid were used as the solvent. X-ray diffraction results show that the as-prepared sample is a pure La
1/2
Na
1/2
TiO
3
with an acubic perovskite-type structure. The mean crystallite sizes were controlled by varying annealing temperatures. FTIR and Raman measurements reveal nano-size effects on the vibration spectroscopic properties of the nanocrystalline La
1/2
Na
1/2
TiO
3
.
Fabrication of Co
3
O
4
Ultrafines by a Liquid-control-precipitation Method
LI Ya-Dong, HE Yun-Pu, LI Long-Quan, QIAN Yi-Tai
1999, 20(4): 519-522.
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Aliquid-control-precipitation(LCP) method to prepare Co
3
O
4
ultrafines was reported in this paper. The results shown that non-agglomerated and well dispersed Co
3
O
4
ultrafine particles with the averages size of 9 nm were successfully prepared only by a liquid control precipitation technique without adding any polymer protecting agent. The LCP method possesses the advantage of simple processing, cheap cost and high yield.
Observation of the Different Binding Rates of Δ-and Λ-[Ru(bpy)
2
(HPIP)]
2+
with Calf Thymus DNA via CD Spectra
LIU Jin-Gang, YE Bao-Hui, JI Liang-Nian, TIAN Xuan, FU Yao-Hong
1999, 20(4): 523-525.
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The complexes of Δ-and Λ-[Ru(bpy)
2
(HPIP)]
2+
(bpy=2,2'-bipyridine, HPIP=2-(2-hydroxyphenyl)imidazo [4,5-f][1,10]phenanthroline) were prepared and their racemic complex were dialysed against calf thymus DNA(CT-DNA). During the course of dialysis with the solution stirring for 48h, the CD signals of the dialyzate experience disappearing-appearing-disappearing. However, in the similar conditions except for not stirring, strong CD signals appeared. From the results obtained, several novel opinions were suggested. Firstly, the evidence of different binding rates of Δ-andΛ-enantiomers of polypyridyl ruthenium(Ⅱ) complexes with CT-DNA, the first example, was demonstrated. As for the dialysis experiment, binding of -enantiomer is dynamically preferred for CT-DNA. Secondly, the different binding rates may be deduced from different binding modes of the enantiomers.
Encapsulation of the Functional Supramolecular Material Between MCM-41 and Rhodamine B and Its Luminescence
ZHANG Mai-Sheng, LIU Wei-Jiang, YANG Yan-Sheng, CHEN Jie-Sheng, FENG Shou-Hua, XU Ru-Ren
1999, 20(4): 526-528.
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In this investigation, mesoporous molecular sieve MCM-41 was synthesized with tetraethyl orthosilicate(TEOS) as the source of silica and cetyltrimethylammonium bromide(CTABr) as the template for the first time by microwave radiation method. The products obtained by microwave radiation method gave similar XRD and SEM photograph with that by hydrothermally synthesized method. While our products possess a spherical hexagon and the diameter of the crystal powder is about 10m. The encapsulation of the functional supramolecular material between MCM-41 and rhodamine Bwas prepared under vacuum condition, the product was characterized by XRD, TG, IR, SEM and fluorescent spectrum. The results showed that the RB
+
ions have entered into the channel of MCM-41 and formed the centers of luminescence, hence the functional supramolecular material with strong luminescence under UVexcitation was obtained. The peak values of the excitation and emission spectra are 335.2 and 587.2 nm, respectively.
Kinetic Spectrophotomatric Determinations of Mixtures of Iron, Zinc and Copper Using Artificial Neural Networks
NI Yong-Nian, LIU Chao
1999, 20(4): 529-533.
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In this paper, chemometric approaches were applied to the simultaneous kinetic analysis of ternary mixtures of iron, zinc and copper. The analysis of these metals was based on the displacement reaction of their EGTA complexes by PAR with the differential reaction rates. The measurement data were then processed by artificial neural networks(ANN), giving a relative standard error of 1.63%, 3.29% and 4.41% for iron, zinc and copper, respectively. The proposed method was also applied to the analysis of feed additive samples with satisfactory results as compared with that obtained by ICP-AES.
Comparison of Wavelet Transform Methods The Compression of IR Spectral Data
ZHANG Wen-Jun, XU Lu, LIU Sheng-Xiong
1999, 20(4): 534-538.
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In this paper, an introduction of wavelet transform and multi-resolution analysis is presented. We describe three data compression methods based on wavelet transform for spectra LIN formation, and by using the multiresolution analysis, we compressed spectral data by Daubechiess compactly supported orthogonal wavelet and orthogonal cubic Bsplines wavelet.Using orthogonal cubic Bsplines wavelet and coefficients of sharpening signal are set to zero, only very few large coefficients are stored, and a favourable data compression can be achieved.
Separation of Enantiomers by Micellae Electrokinetic Chromatography with Chiral Surfactant
FU Xiao-Yun, LU Jian-De, XU Xiu-Zhu, WANG Miao
1999, 20(4): 539-543.
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Several synthetic chiral surfactants such as Ndodecanoyl or NtetradecanoylLamino acids were used as the chiral selector respectively. The neutral, acidic and basic enantiomers such as chloropropionanilide, 2-amino-3-(4-nitrophenyl)-1,2-propanediol and warfarin were separated by MEKC. The effects of the type and concentration of chiral surfactants, pHof buffer solution on the enantiomeric separation were investigated. The results showed that the side group of amino acid and the chain length of hydrophobic alkyl group in chiral surfactant molecule had a significant influence on the separation. The concentration of chiral surfactant was an important factor influencing the enantiomeric separation. Both retention time and resolution increased with increasing the concentration of chiral surfactant. The optimum concentration was in the range from 100 to 150 mmol/Lfor the test samples. The pH of buffer solution had a dramatic effect on separation of the weak basic or acidic enantiomers, but little effect on neutral enantiomer. Under the selected condition, several test enantiomers were successfully separated. The separation efficiency was more than 1×10
5
theoretical plates permeter.
Fluorescence Immunoassay for HBsAg Using a Thermal Phase Separating Polymer
ZHU Qing-Zhi, YANG Huang-Hao, LI Dong-Hui, XU Jin-Gou, ZHANG Yi, ZHANG Chang-Gong
1999, 20(4): 544-548.
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Anovel fluorescence immunoassay for HBsAg was developed by using poly-N-iso-propylacrylamide(PNIP) as an immunoreaction carrier. In sandwich immunoassay, after two steps immunoreaction, PNIP precipitates out of water above a critical temperature of 31℃ , enabling a polymer-bound immune complex to be separated from the solution. The calibration graph for HBsAg was linear over the range of 0.5-100 g/mLwith a detection limit of 10ng/mL. This method combines some advantages of both homogeneous and heterogeneous immunoassays, and has been applied to determining the HBsAg in human blood serum with satisfactory results.
A Study of Electrochemical Process of Fe(CN)
6
3-
/Fe(CN)
6
4-
on Gold Electrode by Electrochemical Quartz CrystaLImpedance System
XIE Qing-Ji, WANG Jin, XU Zhi-Nian, LIU Hong-Wei, ZHANG You-Yu, YAO Shou-Zhuo
1999, 20(4): 549-551.
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Admittance spectra of quartz crystal resonance were measured in situ in the electrochemical process of Fe(CN)
6
3-
/Fe(CN)
6
4-
on Au electrode in 10mol/L Na
2
SO
4
aqueous solution using an electrochemical quartz crystaLImpedance system. Changes in motional resistance R
1
were well reversible with potential, but resonant frequency f
0
, series resonant frequency f
s
and parallel resonant frequency f
p
had significant rising drifts besides somewhat reversible changes with potential. It is concluded that changes in R
1
were caused by variations in solution density and viscosity near electrode surface, but frequency responses resulted from both changes of solution properties and corrosion of Au electrode in anodic process.
Preparation and Evaluation of a Mixed Functional Stationary Phase Containing Crown Ether and Cyclodextrin for Highperformance Liquid Chromatography
FENG Yu-Qi, GONG Yin-Han, DA Shi-Lu
1999, 20(4): 552-554.
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Amixed functional stationary phase containing aza crown ether and cyclodextrin for highperformance liquid chromatography was prepared via a continuous solidliquid reaction method. The new mixed functional stationary phase was used to separate some disubstituted benzene isomers such as nitrophenols, nitroanilines and phthalic acids. The results show that the separation ability of the new mixed functional stationary phase for the disubstituted benzene isomers is better than that on the aza crown ether bonded silica and cyclodextrin bonded silica stationary phases. Chiral separations of glycine derivatives, PMGly, MPGly and BPGly, were partially achieved on the new mixed functional stationary phase with phosphate buffer solution as the mobile phase.
Studies on the Application of Synthesized Near-IR Cyanine to the Determination of Trace Amounts of Protein
ZHENG Hong, LI Dong-Hui, WU Min, XU Jin-Gou, CHEN Qiu-Ying
1999, 20(4): 555-557.
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Anew watersoluble near-IRcyanine dye was synthesized and its structure was characterized by
1
HNMR, MS and IR spectra. The dye was used as a probe to establish a novel near-IR spectrophotometric method for the determination of trace amount of serum protein. The dye has a maximum absorption wavelength at 776nm, its absorbance decreases when it reacts with protein(for example, BSA). The reaction of the dye with BSA was carried out in 0.02mol/L HAc-NaAc buffer system(pH4.0). When 3.0×10
-6
mol/Lcyanine was used, the linearity of this method was over the range of 1.00×10
2
-1.90×10
3
ng/mL by determination of HSA and globulin, and the detection limit was 50ng/mL.
Studies on Electrospray Mass Spectrometry of Some Narcotic Drugs
SONG Feng-Rui, LIU Zhi-Qiang, SUN Wei-Xing, LIU Shu-Ying, HUANG Hai-Wei
1999, 20(4): 558-560.
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Using electrospray ionization(ESI) and tandem mass spectrometry techniques, the protonic positions in protonated molecular ions of some narcotic drugs were studied. The data of ESI/MS
n
experiments of morphine and deuterium-loaded morphine were first discussed. The protonic position was considered to locate on oxygen atom of cyclic ether in morphine molecular. Compared with the same and different ions among morphine, codeine, acetylcodeine and dihydrocodeine, the protonic positions in protonated molecular ions of these compounds were further determined. The fragmentation mechanism of morphine in ESI/MS
n
experiments was also repored in the paper, and there were similar dehydrolysis mechanism in gas phase or in liquid phase for morphine.
Synthesis of Cage Heterocyclic Compounds with High Strain
OU Yu-Xiang, XU Yong-Jiang, CHEN Jiang-Tao, CHEN Bo-Ren, ZHENG Fu-Ping, JIA Hui-Ping, WANG Cai
1999, 20(4): 561-564.
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Starting from hexabenzylhexaazaisowurtzitane(HBIW), four
N
-substituted hexaazaisowurtzitanes were synthesized via selective and catalytic hydrogenolysis debenzylation by using Pd(OH)
2
/C as catalyst and under mild reaction conditions. In the debenzylation process, partial or all benzyl groups were displaced by other functional groups, such as CH
3
CO_, CHO_ and C
2
H
5
_ etc.. The prepared compounds are all cage heterocyclic ones with high strain and can be used as precusors for synthesis of hexanitrohexaazaisowurtzitane(HNIW). HNIW is the most attractive high energy density compound(HEDC) with most promising application in military field.
Isolation, Characterization and Properties of Spirulina Glycoprotein
YIN Gang, LIU Zheng, LI Chen, LIU Fei, DING Fu-Xin, YUAN Nai-Ju
1999, 20(4): 565-568.
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Aglycoprotein was isolated from Chinese spirulina. Purification of this glycoprotein was accomplished by foam in a loop bubble column and gel chromatography on Sephacryl S-100.The homogeneity of this glycoprotein was proven by gel filtration on Sepha-dex G-200 and SDS-PAGE. The molecular weight of the glycoprotein was 130000. Characterization of this glycoprotein by IR analysis showed the typical absorption of polysaccharide and indicated the presence of
α
-glycoside linkage.
β
-Elimination reaction demonstrated the existence of
ο
-glycosidic linkage in this spirulina glycoprotein.
Studies on the Synthesis of 2-(2-Bromophenyl)oxazoline
LIU Chun, JIANG Jing-Yang, LIU Xiao-Hang, JIN Zi-Lin
1999, 20(4): 569-572.
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The synthetic method for 2-(2-bromophenyl)oxazoline was modified. The condensation reaction of
N
-(
β
-hydroxyethyl)-
o
-bromobenzamide to corresponding oxaozoline is performed by using SOCl
2
, not NaH reagent, with a elevated yield of up to 84%. The experimental results show that the reaction temperature has a great influence on the oxazoline yield. The oxazoline yield drop obviously with the rising of the reaction temperature and at room temperature hardly any oxazoline product formed. Based on the results obtained, it is presumed that ehe oxazoline ring was formed via an imide tautermer intermediate.
Microwave Irradiated Synthesis of Benzo phenoxazine Derivatives in Solid State
LONG Jiang, JIN Jin, WANG Yong-Mei, MENG Ji-Ben
1999, 20(4): 573-576.
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Anew methodology quickly leading to benzo phenoxazine derivatives is reported. The mixture of
N
,
N
-dialkyl-4-nitrosoaniline hydrochloride and 2-naphthol derivatives was irradiated in domestic microwave oven in the absence of solvent to afford benzoa[a] phenoxazonium chlorides 3a_3f with a high yield and the results were compared with the conditions reacted in supporters, oilbath or solvent. Moreover, a new laser dye 9-dimethylamino-6-carbethoxy-5H-benzo phenoxazin-5-one was prepared.
Progress in Tin and Molybdenum(Tungsten) Bonded Polymetallic Complexes
TANG Liang-Fu, WANG Zhi-Hong, WANG Ji-Tao
1999, 20(4): 577-583.
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In this paper the advance of tin and molybdenum(tungsten) bonded polymetallic(especially bimetallic) complexes in recent years was described. These complexes show different structural characteristics and reactivities according to various ligands around the central metals of tin and molybdenum(tungsten).
The Regulation of Mg(Ⅱ) to the Combination of Ciprofloxacin and Calf Thymus DNA
GUO Dong-Sheng, YUAN Xiao-Ying
1999, 20(4): 584-586.
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Using the method of fluorescence, the binding constants of ciprofloxacin(CPFX)-Mg(Ⅱ)and CPFX-calf thymus DNA(C. T. DNA), the formed quantity and the forming condition of ternary complex of CPFX-Mg(Ⅱ)-C.T.DNA have been determined. Adding Mg(Ⅱ) to the binary system of CPFX with C.T.DNA, the binding quantity of CPFXwith C.T.DNAincreases to the largest, then decrease up to zero in the end as the increase of the concentration of Mg(Ⅱ). The result shows the amount of CPFX bound to C.T.DNA is modulated by Mg(Ⅱ), and in the concentration of Mg(Ⅱ) precented in eucaryotic organism cytoplasm, CPFX has no obvious combination with C. T. DNA.
A Stereoselective Reductive Rearrangement of Allylic Epoxyalcohols New Synthetic Method of 1,3-Diol
TU Yong-Qiang, XIA Wu-Jiong, WANG Ping-Zhen, ZHAI Jian-Jun, CHEN Yao-Zu
1999, 20(4): 587-589.
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Anovel method for synthesis of stereoselective 1,3-diol from hydroxyepoxides was developed by reductive rearrangement with aluminum isopropoxide, which is very convenient and efficient. The substituted effect and stereochemistry were also discussed.
Stereoselective Synthesis of Lthreodihydrosphingosines
DU Hong-Wang, CHENG Jian-Xin, HAO Jun-Sheng, PAN Ji-Gang, XIA Chi-Zhong
1999, 20(4): 590-592.
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This paper has developed a short, practical, highly stereoselective synthetic approach to
L
-threo-dihydrosphingosines from
L
-serine. All compounds were substantiated by MS, IR,
1
HNMR and elementary analysis. The spectra data of 6b were in agreement with those from literature.
Theoretical Research on the Electronic Structure, the UV-Vis, NMR Spectra and Nonlinear Secondorder Optical Property of C
59
(CHPh
2
)N
REN Ai-Min, FENG Ji-Kang, SUN Xiu-Yun, GUO Jing-Fu, PAN Ge-Bo, LI Wei, SUN Chia-Chung
1999, 20(4): 593-597.
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In this paper, we have made a theoretical research on the substituted azafullerene C
59
(CHPh
2
)N synthesized from (C
59
N)
2
and CH
2
Ph
2
using the INDO series methods. The stable molecular configuration of C
59
(CHPh
2
)N have been obtained, which shows that C
59
(CHPh
2
)N is C
s
symmetry. On the basis of above geometry, the UV-Vis and NMR spectra of C
59
(CHPh
2
)N have been calculated and discussed. The results are in good agreement with experimental results. The nonlinear secondorder optical susceptibility of C
59
(CHPh
2
)N have been calculated too, and the result shows that this molecule has quite a big nonlinear secondorder optical susceptibility.
A Theoretical Study on Geometric Structures and Electronic Properties of Cluster Ions Ti
n
P
m
+
TAN Kai, LIN Meng-Hai, WU Wei, ZHENG Lan-Sun, ZHANG Qian-Er,
1999, 20(4): 598-602.
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The cluster ions Ti
n
P
m
+
generated by laser plasma reaction have been studied by using quantum chemistry
ab initio
method. The possible geometric structures were examined and optimized. For TiP
m
+
, titanium atom tends to combine with two phosphorus atoms to form planar systems, while TiP
4
+
and TiP
6
+
are more stable than another. There is one growing helix for Ti
2
P
4
+
-Ti
2
P
8
+
, the number of phosphorus atoms between two titanium atoms grows from four to eight, and these phosphorus take the shapes of tetrahedron, pentagon, octahedron or cube, etc. It is found that Ti
3
P
m
+
and Ti
4
P
m
+
in many titanium phosphide are more stable.
Studies on Liquid Membrane Iodide Selective Electrode with Long Lifetime and High Selectivity
ZENG Yun-Long, TANG Chun-Ran, SHENG Guo-Li, YU Ru-Qin
1999, 20(4): 603-607.
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PVC-DZT-Hg(Ⅱ) compound was synthesized and used to prepare a high selectivity iodide electrode. The selectivity order of the electrode is I
-
》ClO
4
-
>SCN
-
>NO
2
》
-
Sal
-
Br
-
>NO
3
-
>Cl
-
. The electrode has a linear response to iodide from 1×10
-3
to 5×10
-7
mol/Lwith a detection limit of 2×10
-7
mol/Land a slope of (59±1) mV/decade(16℃ ). The response mechanism of the electrode was investigated by spectroscopic techniques. It was demonstrated that iodide anion acts with Hg in the carrier. The electrode was satisfyingly used for the determination of iodine content in the salts from different markets.
Studies of the V
2
O
5
/MPO
4
(M=Al, Zr, Ca) Catalysts in Propane Oxidative Dehydrogenation
ZHANG Wei-De, SHA Kai-Qing, LI Ji-Tao, WAN Hui-Lin
1999, 20(4): 608-611.
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The supports of MPO
4
(M=Al, Zr, Ca) were prepared and 0.6%~60%V
2
O
5
was supported on them. The catalysts are effective in the oxidative dehydrogenation of propane. The selectivity of C
3
H
6
over the catalysts decreases in the order of V
2
O
5
/Ca
3
(PO
4
)
2
>V
2
O
5
/Zr
3
(PO
4
)
4
>V
2
O
5
/AlPO
4
, which followed the same trend of the basicity of the supports. The properties of the supports and the amount of loading had an effect on the redox property and the catalytic behavior of the catalysts. The ESR results indicated that the redox couple of V
5+
/V
4+
responded to the activity of oxidative dehydrogenation for propane.
Theoretical Study on the Cycloaddition Reaction of Dichlorosilylene and Ethylene or/and Formaldehyde
LU Xiu-Hui, WANG Yi-Xuan, LIU Cheng-Bu
1999, 20(4): 612-615.
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The mechanism of the cycloaddition reaction of singlet dichlorosilylene and ethylene or/and formaldehyde has been studied by RHF/6-31G
*
gradient method. The electron correlation energies of all the structures are calculated by using second-order Moller-Plesset perturbation theory(MP
2
). The results show that the two reaction proceesses are both two steps: (1) dichlorosilylene and ethylene or/and formaldehyde form an intermediate complex respectively, which is a exothermal reaction with no barrier; (2) two intermediate complexes isomerized to the products respectively, the barriers of the two reactions are 97.43 and 103.29 kJ/mol at MP
2
/6-31G
*
//6-31G
*
with zero-point energies correction level.
The Interaction Between Sb
2
O
3
and HZSM-5
ZHU Shu, MENG Xian-Ping, WANG Ying-Xia, ZHANG Wan-Jing, LIN Bing-Xiong, LIU Xi-Yao
1999, 20(4): 616-619.
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The behavior of Sb
2
O
3
on HZSM-5 was investigated by employing the techniques such as XRD, N
2
and
n
-hexane adsorption, NH
3
-TPD etc.. Mechanic mixture of Sb
2
O
3
and HZSM-5 was calcined at 500℃ under nitrogen for two hours. XRD results showed that crystalline Sb
2
O
3
disappeared while HZSM-5 framework suffered a noteworthy damage.Quantitative phase analysis indicate that the crystalline HZSM-5 amount in Sb
2
O
3
/HZSM-5 shrank from 76% to 59% after calcination. The Sb
2
O
3
/HZSM-5 to HZSM-5 ratios of pore volumes (derived from N
2
adsorption experiment) and
n
-hexane saturated adsorption amount were 0.60 and 0.62, both corresponding to that ratio of the crystalline HZSM-5 amount(0.59/0.95=0.62). The fact suggests that in calcined Sb
2
O
3
/HZSM-5, nothing exists in the channels of the zeolite. Moreover, it is also found that the
n
-hexane saturated adsorption pressure of Sb
2
O
3
/HZSM-5 is greater than that of HZSM-5. Based on the results above, a new mechanism of the interaction between Sb
2
O
3
and HZSM-5 was proposed. During calcination, the framework of HZSM-5 is partly broken by acidic Sb
2
O
3
, which in turn highly disperses into the silica-alumina gel yielded from framework collapse. This gel modifies the external-surface of HZSM-5 by diminishing its pore openings, subsequently enhancing the shape-selectivity of the zeolite. Toluene alkylation reaction was applied to characterize Sb
2
O
3
/HZSM-5, the
para
-selectivity attained as high as 89%.
Self-assembled Au Nanoparticles on GaAs and Its Surface Enhanced Raman Scattering(SERS)-activity
CHEN Hai-Feng, WANG Jian, CAI Sheng-Min, LIU Zhong-Fan
1999, 20(4): 620-623.
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By using
p
-aminothiophenol(PATP) as the coupling molecular, the Au nanoparticles were successfully self-assembled onto the GaAs(100) surface. Firstly, the mechanically polished semi-insulating GaAs(100) wafers were degreased in trichloroethylene, acetone, methanol, and the surface oxides were chemically polished and removed by rinsing them in
V
(H
2
SO
4
)
V
(H
2
O
2
)
V
(H
2
O)=3:1:1,
V
(NH
4
OH)
V
(H
2
O
2
)
V
(H
2
O)=1:1:7, HCl and de-ionized water. Then the wafers were dried with argon and immediately immersed in1 mmol/Lethanol solution of PATP. After assembling in the solution for 24 h with argon protection, the GaAs(100) wafers with PATP SAMs were ultrasonicated in pure ethanol to remove those physical adsorbed PATP molecules. Assembling of gold nanoparticles(70nm) were handled by immersing thus prepared GaAs(100) wafers with PATP SAMs in a colloidal gold suspension for 6h. The gold nanoparticles were scattered over such a surface. Thus the prepared samples showed a surface enhanced Raman scat tering(SERS)-activity.
Ordered Nano-structured Polymer Films of PATP/PANI by Electrochemical-assembly
ZHANG Hong-Ping, LUO Jin, HUANG Huai-Guo, WU Ling-Ling, LIN Zhong-Hua
1999, 20(4): 624-628.
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The ordered two-dimensional nano-structured conducting polymer films of a
p
-aminothiolphenol/polyaniline(PATP/PANI) on Au is fabricated by electrochemical-assembly (ECA) which is a new method first reported by our group. The surface topography, property and structure of PATP/PANI polymer films were investigated using scanning tunneling microscopy(STM), surface enhanced Raman scattering (SERS) and cyclic voltammetry. The results indicate that such oligomer films comprise ordered nano-structured clusters. The surface of the films is close-packed, homogeneous, flat in two-dimension. The electron transfer performance of PATP/PANI films is rather high.
Transport Property and EPR Studies for La
1-x
Li
x
MnO
3
System
ZHOU Xian-Feng, LI Li-Ping, SONG Xiao-Yu, MIAO Ji-Peng, SU Wen-Hui
1999, 20(4): 629-633.
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The perovskite oxides La
1-x
Li
x
MnO
3
were prepared by solid state reactions. The XRD results indicate that all samples crystallize in rhombohedral structure. Except
x
=0, 0.3 ones, all samples show a transition from insulator to metal with decreasing temperature within the liquid nitrogen temperature region, where
x
=0.15 sample exhibits the highest transition temperature. The negative magnetoresistance phenomena is observed at applying the magnetic field with
H
=1.0 T. The EPRsignal with
g
=2.00 is closely related with the complex of Mn
3+
-Mn
4+
clusters.
Enhancement of Glucose Biosensor Sensitivity by Addition of Silver Sols
TANG Fang-Qiong, SHEN Ji-Feng, ZHANG Jin-Fang, ZHANG Gai-Lian
1999, 20(4): 634-636.
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Anew method for preparation of amperometric glucose oxidase electrode based on enzyme immobilization by Ag sols has been investigated. GOD was simply mixed with Ag nanoparticles and cross linked with a polyvinyl butyl(PVB) medium by glutaradehyde and was coatted on electrode by dipping a platinum wire into the sol-gel solution. In experiments, we discussed the effects of different kinds of silver gels on response of the electrode and the mechanism about it. For the optimum conditions, the current response of the enzyme electrode containing hydrophobic silver gels for 10 mmol/Lglucose was enhanced to 18200 nAas compared with the electrode without silver gels with 280n Acurrent response. In addition to the high sensitivity, the electrode responses rapidly, the 95% steady-state response time is less than 20s.
Preparation, Characterization and CO Oxidation of Nanometer Co
3
O
4
JIA Ming-Jun, ZHANG Wen-Xiang, TAO Yu-Guo, WANG Gui-Ying, CUI Xiang-Hao, ZHANG Chun-Lei, WU Tong-Hao, DONG Guo-Qiang, LI Xue-Mei
1999, 20(4): 637-639.
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Various nanometer Co
3
O
4
samples were prepared and the catalytic performance of COoxidation were examined. It was found that the activities of the catalysts were greatly changed with variation of the preparation methods and pretreatment conditions. Among the samples tested, Co
3
O
4
prepared by using dodecylbenzene sulfonic acid sodium salt(DBS) as the surfactant, calcined at 300℃ showed the highest activity and it was able to oxidize completely CO even at -78℃ . Characterization of these samples by XRD and BET means showed that the catalytic acitivity increased with the decrease of the average particle size, suggests that the average particle size of nanometer Co
3
O
4
samples is the main controlling factor of the catalytic activity.
Styrene Epoxidation with t-Butyl Hydroperoxide Catalyzed by Nanometer TiO
2
(Ⅰ)
QI Jian-Ying, YANG Qi-Yun, LIU Zheng-Yi, LI Xian-Jun
1999, 20(4): 640-642.
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The catalysts of nanometer TiO
2
/EtOH, nanometer TiO
2
/#em
/em#-PrOH and nanometer TiO
2
/EtOH-BuOH were prepared by the liquid-phase method from Ti(SO
4
)
2
in different alcohols. The properties of the catalysts were characterized by TG-DTA, IR, XRD and TEM methods. The results showed that the nanometer TiO
2
/#em
/em#-PrOH was 20nm×20nm anatase particle with an excellent thermal stability. The activities and selectivities of the catalysts in styrene epoxidation with t-butyl hydroperoxide(TBPH) were studied and compared with the commercial TiO
2.
When the oxidation was carried out under a suitable condition the main product and by product were styrene peroxide and phenylformaldehyde, respectively. The conversion of styrene and the selectivity of epoxide at 80 were 33.4% and 70.2% over the catalyst of nanometer TiO
2
/#em
/em#-PrOH, respectively. The activity of commercial TiO
2
was only 1/3 that of nanometer TiO
2
/#em
/em#-PrOH. The
iso
-propanol supported nanometer TiO
2
improved obviously the activity and selectivity in the epoxidation of styrene.
Crystal Morphology of Poly(aryl ether ketone)s Containing MetaPhenyl Links
KE Yang-Chuan, QI Zong-Neng, WU Zhong-Wen
1999, 20(4): 643-646.
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The crystal morphology of low molecular weight poly(aryl ether ketone)s containing metaphenyl links has been investigated by TEM techniques. Results show that there exists a new crystal morphology in the polymer crystallites, that is quadrant angular leaflike single crystals, the angular degrees between the two diagonals of which are 101.9° , which is in good agreement with the 102.6° obtained from the calculation of unit cell crystal parameters. The above morphology has directly shown that these kinds of poly(aryl ether ketone)s containing metaphenyl links has its crystal unit cell growing along the (110) crystal face while its spheruletics grow along its crystal
b
axis.
The Preparation and Exchange Reaction Characteristics of Central Nervous System Drugs-resin Complexes
LI Zhen-Hua, PI Hong-Qiong, REN Guang-Zhi, HE Bing-Lin
1999, 20(4): 647-650.
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In this paper the effect of the chemical structures of various drugs such as dextromethorphan hydrobromide(DM), pseuoephedrine hydrochloride(PE) and phenylpropanolamine hydrochloride(PM) on the exchange behavior with the strongly acidic cation exchanger(0017) was described. From experiments, it indicates that the exchange rate constants were found to be 1.041×10
-3
±2.56×10
-5
, 2.290×10
-2
±1.24×10
-4
, 2.40×10
-2
±1.02×10
-4
min
-1
at 25℃ respectively. The K
e
is increased with increasing temperature. The exchange activation energies were calculated to be 50.26, 21.68, 20.83 kJ 5mol
-1
, respectively. The apparent equilibrium constants(K
e
) were calculated to be 3.235±0.252, 3.680±0.214, 4.510±0.328 at 25 , respectively. The exchange reactions are spontaneous according to the data of
G
=-2.909±0.0205, -3.228±0.0181, -3.732±0.0127 kJ 5mol
-1
, respectively. The reaction enthalpy
H
were found to be 88.44±5.548, 48.29±3.214, 48.66±3.158 kJ 5mol
-1
, respectively, indicating the reaction is enthermal reaction.
Kinetics of Vinyl Monomer/
N
-Substituted Maleimide Copolymerization
SHAN Guo-Rong, WENG Zhi-Xue, HUANG Zhi-Ming, PAN Zu-Ren
1999, 20(4): 651-655.
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The effects of reaction temperature, initiator concentration, and molar fraction of monomer on the copolymerization kinetics of styrene/
N
-phenylmaleimide were studied in detail. The copolymerizations of styrene, methyl methacrylate, acrylonitrile, or their mixtures with
N
-phenylmaleimide,
N
-cyclohexylmaleimide, or
N
-(
o
-chlorophenyl)maleimide were also investigated and discussed with the structure of comonomer pairs.
Reactivity Ratios for Copolymerization with theParticipation of Chargetransfer Complex
SHAN Guo-Rong, WENG Zhi-Xue, HUANG Zhi-Ming, DU Miao, PAN Zu-Ren
1999, 20(4): 656-660.
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On the basis of the propagation elementary reactions for copolymerization with the participation of chargetransfer complex(CTC), a measuring method of reactivity ratios was presented. Four reactivity ratios, the relative reactivity of free monomer and chargetransfer complex could be obtained. They were r
12
=0.03370, r
21
=0.01157, r
1C
=0.002972, r
2C
=0.003379, and k
1C
/k
12
=11.3375, k
2C
/k
21
=3.4238 for styrene/
N
-phenylmaleimide copolymerization. The result was compared with that measured by MayoLewis model.
A Study of Solution Technique for Modifying Polymer Surfaces(Ⅰ) Surface Structure and Properties of Modified Polymer Surfaces
SUN Yong-Hong, YUAN Jun, QIU Yong-Xing, ZHENG Xiao-Xiang, FENG Lin-Xian
1999, 20(4): 661-663.
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This article reports a simple and effective method for modifying polymer surface. The modified polymer surfaces are characterized by
1
HNMR, ESCAand water contact angle. The hydrophilicity of model polymer PSsurface can be greatly increased. The PEO polar component is found to be concentrated at modified polymer filmair interface, which is benefit for the introduction of bioactive substances.
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